Find all School-related info fast with the new School-Specific MBA Forum

It is currently 22 Oct 2014, 08:18

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

On Monday, a person mailed 8 packages weighing an average

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23375
Followers: 3607

Kudos [?]: 28780 [1] , given: 2847

On Monday, a person mailed 8 packages weighing an average [#permalink] New post 13 Aug 2012, 05:57
1
This post received
KUDOS
Expert's post
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

78% (04:09) correct 22% (01:24) wrong based on 392 sessions
On Monday, a person mailed 8 packages weighing an average (arithmetic mean) of 12\frac{3}{8} pounds, and on Tuesday, 4 packages weighing an average of 15\frac{1}{4} pounds. What was the average weight, in pounds, of all the packages the person mailed on both days?

(A) 13\frac{1}{3}

(B) 13\frac{13}{16}

(C) 15\frac{1}{2}

(D) 15\frac{15}{16}

(E) 16\frac{1}{2}

Practice Questions
Question: 16
Page: 154
Difficulty: 600
[Reveal] Spoiler: OA

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23375
Followers: 3607

Kudos [?]: 28780 [1] , given: 2847

Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 13 Aug 2012, 05:57
1
This post received
KUDOS
Expert's post
2
This post was
BOOKMARKED
SOLUTION

On Monday, a person mailed 8 packages weighing an average (arithmetic mean) of 12\frac{3}{8} pounds, and on Tuesday, 4 packages weighing an average of 15\frac{1}{4} pounds. What was the average weight, in pounds, of all the packages the person mailed on both days?

(A) 13\frac{1}{3}

(B) 13\frac{13}{16}

(C) 15\frac{1}{2}

(D) 15\frac{15}{16}

(E) 16\frac{1}{2}

The total weight of 8 packages is 8*12\frac{3}{8}=99 pounds;

The total weight of 4 packages is 4*15\frac{1}{4}=61 pounds;

The average weight of all 12 packages is \frac{total \ weight}{# \ of \ packages}=\frac{99+61}{12}=13\frac{1}{3}.

Answer: A.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Manager
Manager
avatar
Joined: 30 Sep 2009
Posts: 110
Followers: 0

Kudos [?]: 14 [0], given: 85

GMAT ToolKit User
Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 13 Aug 2012, 07:46
a person mailed 8 packages=99 pounds (total of all 8 packages)

and on Tuesday, 4 packages=61 pounds (total of all 4 packages)

total weight =99+61 =160 pounds

the average weight =160/(8+4) =option a
Senior Manager
Senior Manager
avatar
Joined: 14 May 2011
Posts: 277
Location: Costa Rica
Concentration: Healthcare, International Business
GMAT 1: 640 Q V0
GMAT 2: 710 Q42 V45
GMAT 3: 740 Q48 V42
GMAT 4: Q V0
GMAT 5: Q V0
GPA: 3.3
WE: Research (Consulting)
Followers: 11

Kudos [?]: 69 [0], given: 134

Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 16 Aug 2012, 10:10
Bunuel wrote:
RESERVED FOR A SOLUTION.


Bunuel, had an off-topic request for you: Could you please post questions from non-OG sources as well? I'm not sure if that might breach a copyright arrangement bsaed on the source you use, and of course your comments on other's questions are supremely valuable for those of us subscribed to your daily updates - but if you could include occasional 700+ non-OG questions, would be much appreciated by your "followers"
:)
_________________


How to improve your RC score, pls Kudo if helpful! http://gmatclub.com/forum/how-to-improve-my-rc-accuracy-117195.html
Work experience (as of June 2012)
2.5 yrs (Currently employed) - Mckinsey & Co. (US Healthcare Analyst)
2 yrs - Advertising industry (client servicing)

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23375
Followers: 3607

Kudos [?]: 28780 [0], given: 2847

Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 16 Aug 2012, 23:54
Expert's post
SOLUTION

On Monday, a person mailed 8 packages weighing an average (arithmetic mean) of 12\frac{3}{8} pounds, and on Tuesday, 4 packages weighing an average of 15\frac{1}{4} pounds. What was the average weight, in pounds, of all the packages the person mailed on both days?

(A) 13\frac{1}{3}

(B) 13\frac{13}{16}

(C) 15\frac{1}{2}

(D) 15\frac{15}{16}

(E) 16\frac{1}{2}

The total weight of 8 packages is 8*12\frac{3}{8}=99 pounds;

The total weight of 4 packages is 4*15\frac{1}{4}=61 pounds;

The average weight of all 12 packages is \frac{total \ weight}{# \ of \ packages}=\frac{99+61}{12}=13\frac{1}{3}.

Answer: A.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 03 Sep 2012
Posts: 3
Followers: 0

Kudos [?]: 0 [0], given: 5

Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 07 Sep 2012, 09:09
There must be something easy that i just don't get for me :
8*12(3/8) = 36 as you simplify the 8 between them. Therefore how do you manage to arrive at 99?

I guess it must be something different of spelling or something?

Thanks a lot for your help !
Expert Post
2 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23375
Followers: 3607

Kudos [?]: 28780 [2] , given: 2847

Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 07 Sep 2012, 09:15
2
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
Gmbrox wrote:
There must be something easy that i just don't get for me :
8*12(3/8) = 36 as you simplify the 8 between them. Therefore how do you manage to arrive at 99?

I guess it must be something different of spelling or something?

Thanks a lot for your help !


It's not 12 multiplied by 3/8. it's 12\frac{3}{8}=\frac{12*8+3}{8}=\frac{99}{8} (the same way as 1\frac{1}{2}=\frac{3}{2}).
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 03 Sep 2012
Posts: 3
Followers: 0

Kudos [?]: 0 [0], given: 5

Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 07 Sep 2012, 09:20
Thank you a lot bunuel, Ok after reviewing the official book, i now got it, it is a mix number, it does not exists in france so that's why. If anyone has difficulties to understand like me :

12(3/8) = 12+3/8 and not 12x(3/8).

Can be confusing.
2 KUDOS received
Director
Director
User avatar
Joined: 22 Mar 2011
Posts: 612
WE: Science (Education)
Followers: 73

Kudos [?]: 529 [2] , given: 43

Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 07 Sep 2012, 10:47
2
This post received
KUDOS
Since the final average cannot be greater than 15\frac{1}{4}, answers C, D and E are out.

We can use the property of weighted averages.
15\frac{1}{4}=15\frac{2}{8}, the distance between the two initial averages is almost 3.
Since the number of packages are in a ratio of 8:4 = 2:1, the differences between the final average and the initial averages are in a ratio 1:2.
So, the distance between 12\frac{3}{8} and the final average is almost 1, close to 12\frac{3}{8}+1\approx{13}\frac{1}{4}.
The final answer should be close to 13\frac{1}{4}.

Answer A.
_________________

PhD in Applied Mathematics
Love GMAT Quant questions and running.

CEO
CEO
User avatar
Joined: 09 Sep 2013
Posts: 2828
Followers: 206

Kudos [?]: 42 [0], given: 0

Premium Member
Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 26 Oct 2013, 03:38
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Intern
Intern
avatar
Joined: 06 Jan 2013
Posts: 11
Location: United States
Concentration: Finance, Economics
GMAT Date: 11-15-2013
GPA: 3.5
WE: Education (Education)
Followers: 0

Kudos [?]: 6 [0], given: 24

CAT Tests
Re: On Monday, a person mailed 8 packages weighing an average [#permalink] New post 24 Aug 2014, 23:54
I used weighted-averages to solve this as follows:

Let 12.375 be the lowest weight, therefore, (15.25 - 12.375) = 2.875, the difference in weights between the light and heavy packages.

Hence, the amount we need to add to 12.375 is:

(8x0 + 4x2.875)/(8+12) = 11.50 / 12 ~ 12/12 = 1 (Need to round final answer down a bit since I rounded numerator up)

Therefore, the average weight of all packages is approximately 12.375 + 1 = 13.375, since I need to round the numerator down, ans = 13.333, or A
Re: On Monday, a person mailed 8 packages weighing an average   [#permalink] 24 Aug 2014, 23:54
    Similar topics Author Replies Last post
Similar
Topics:
7 Experts publish their posts in the topic To mail a package, the rate is x cents for the first pound Walkabout 8 17 Dec 2012, 05:37
1 Experts publish their posts in the topic To mail a package, the rate is x cents for the first pound miweekend 9 25 Aug 2011, 08:02
In a certain warehouse, 60 % of the packages weigh less than NTLancer 5 08 Apr 2006, 16:03
In a certain warehouse, 60 percent of the packages weigh kdhong 2 28 Dec 2004, 21:52
Display posts from previous: Sort by

On Monday, a person mailed 8 packages weighing an average

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.